I apologize for being a bit short on that fact - I was hoping to avoid a long sidetrack into plant biology, photosynthesis & the Krebs Cycle.
What that boils down to - the fact that we need CO2 in the atmosphere to support plant life, but that the CO2 we generally emit from fossil fuel burning does our plants no favors, is that CO2 put into the atmosphere as a result of burning fossil fuels (and sometimes biomass like wood) rises into a layer of the atmosphere called the tropopause. The tropopause is the border between the portion of the atmosphere we inhabit (the troposphere) and the next layer of our atmosphere (stratosphere). Plants can't get to any of the CO2 in the tropopuase - this is where the greenhouse effect & the ozone layer "live."
The long life of CO2 molecules cited by the article you link to is one of the very big problems here, as the gas is difficult to "get rid of."
Carbon most certianly does cycle in the atmosphere, most gases do, just as water cycles from atmosphere to Earth. To understand the idea I'm explaining it is necessary to continue reading to the paragraph beyond the one you quoted.
" However, the net addition of CO2 to the atmosphere from human activities will take a very long time to be permanently absorbed by oceans, plants, and soil. If you add a pulse of extra CO2 into the atmosphere, only about half of it will be gone from the air a century later. The rest will leave the atmosphere even more gradually, over hundreds and even thousands of years."
Saying that the carbon is "trapped" in our greenhouse layer is merely a mechanism for conveying the fact that it is NOT removed from our air via carbon sinks like plantlife in a jiffy, as many climate change opponents claim, and it is a simplistic view I will admit. The carbon that is "trapped" refers to quantity of the gas, not the molecules themselves. The point is that the carbon in the upper layer of the Troposphere (specifically the tropopause) is not usable by any form of life on this earth as it is unreachable - and contributes to global warming. As it cycles, however, you are right to quote the UCAR article, it is eventually accessible to plantlife, oceans, and our other carbon "sinks."
The point to remember, as both UCAR and I am pointing out - is that atmospheric CO2 is rising - and human generated emissions are behind it
"Actually, fossil fuel burning results in more than 30 billion metric tons of CO2 being added to the atmosphere each year. That’s more than 9,000 pounds for every person on Earth."
Even if that is not the largest source of carbon mass in our atmosphere, it's one we control, and it's doing plenty of damage.
Thank you for your comment!